Capacitive Series Switch Research Articles

Miniatured Phase Shifter

Objective: RF MEMS has emerged as a technology with immense potential for wireless communication and defence applications. In this work, a 5 bit RF MEMS switched line phase shifter is presented using cantilever switch achieving low actuation voltage. Methodology: In this work 5 different phase shifters are designed to get 5 bit phase shift at a particular frequency 10 GHz. The phase shifters consist of stubs like structure designed in the ground of CPW and MEMS capacitive series switches. Solid-state phase shifters based on p-i-n diodes or Field-Effect Transistor (FET) switches are used because they provide a good planar solution at a variety of microwave frequency ranges. Micro Electro Mechanical Systems (MEMS) phase shifters are progress today are mainly have established designs because of which the solid-state switch is replaced by a MEMS switch. Findings: By analysing theoretically and practically the results showed that a novel RF MEMS switch was capable of liberating less than 0.1dB insertion loss and more than 19 dB isolation between input and output ports at 20 GHz .This RF MEMS switch shows a 5V actuation voltage. Switching time of RF MEMS switches is measured using a theoretical approach. The switches demonstrated maximum switching time of 0.1μs. By using this switch a 5-bit miniaturized phase shifter is designed i.e. 180° bit, 90°, 45°, 22.25° and 11.5° bits were achieved using the switched line type phase shifters at 10 GHz. A novel switched line type phase shifter loaded with multiple switch pairs was developed and was capable of liberating a multiple phase shift angles within single design

In‐line RF‐MEMS series switches for reconfigurable antenna applications

AbstractThe air bridged RF‐MEMS capacitive series switches in single pole single throw transmission lines for reconfigurable antenna applications are presented. The RF characteristics of capacitive series switches are analyzed, measured, and compared with microstripline and coplanar‐waveguide, which are generally used for transmission lines of MEMS reconfigurable circuits. RF‐MEMS series switches are fabricated in both transmission lines on a glass substrate (εr = 7.4 and tan δ = 0.001). The reconfigurable beam steering spiral antenna (fo = 11 GHz), which is monolithic integrated with RF‐MEMS capacitive series switches on the same glass substrate, is also presented as an example of the use of in‐line capacitive series switches. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 3130–3134, 2007; Published online in Wiley Inter‐Science (www.interscience.wiley.com). DOI 10.1002/mop.22971

MEMS capacitive series switch fabricated using PCB technology

In this article, an RF MEMS capacitive series switch fabricated using printed circuit processing techniques is discussed. Design, modeling, fabrication, and characterization of the CPW series switch are presented. An example CPW series capacitive switch with insertion loss less than 0.5 dB in the frequency range of 13–18 GHz and isolation better than 10 dB up to 18 GHz is discussed. The switch provides a minimum insertion loss of about 0.1 dB at the self-resonance frequency of 16 GHz and a maximum isolation of about 42 dB at 1 GHz. © 2007 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2007.

Filter-through device: a distributed RF-MEMS capacitive series switch

Micro-electromechanical systems are presented as promising enabling devices for future telecommunication systems and architectures. Capacitive switches in particular have quickly captured the interest of designers and process developers by their apparent simplicity and promises of great performance in terms of linearity, insertion loss, isolation, frequency band of application and level of integration. In practice however, capacitive devices, and especially their series implementation, have proven more subtle to develop than was first thought. This paper presents the design, realization and measurement of a novel type of high performance distributed capacitive series switching device. The structure realizes a MEMS filter-through characteristic using only transmission line resonators and capacitive series switches with modest capacitance ratio. Key characteristics of this design are the use of filter theory to achieve a high isolation and a proper choice of the filter architecture allowing us to modify a narrow passband characteristic into a very wideband through upon actuation of its RF-MEMS building blocks. The device has two functional states, i.e. idle (RF-OFF) and actuated (RF-ON). The filter-through device thus allows a simpler biasing scheme than the combinations of series and shunt switches commonly used for broadband high performance capacitive switching. Between 0.5 and 22 GHz, the measured isolation and insertion loss of the filter-through are better than 50 dB and 2.7 dB, respectively. The major part of the insertion loss is due to the resistive loss in the 8.4 mm long lines and can be improved by minor process changes not involving the MEMS building blocks.